There is no such restriction. You can have launch dimensions completely independent of whatever your display mechanism is.
Though you need to make sure that all buffers used during the post-processing are sized accordingly and since the denoiser stage dimension cannot be set individually the command list needs to be recreated during size changes.
Then there could be potential timeout issues if this is just too much workload for your GPU.
Basically look at all occurrences of the Application class’ m_width and m_height members in this example below.
These follow the current client window width and height, but you could just change that to use an additional pair of m_widthLaunch and m_heightLaunch variables and use that for all image buffers and the launch call.
Not for the OpenGL viewport and mouse interaction (pinhole camera setup) which are client window relative.
Then depending on your GPU configuration, there could still be too much memory used. In that case look at the “maxmem” variable and set that to some smaller limit, e.g. try below 100 MB.
Please always list the following system configuration information when asking about OptiX issues:
OS version, installed GPU(s), VRAM amount, display driver version, OptiX major.minor.micro version, CUDA toolkit version used to generate the input PTX, host compiler version.
Some more precise information with absolute numbers would have been helpful for developers reading this.
You neither said what your screen resolution is nor what launch sizes failed on what system configuration.